A drop-out fuse based on shape memory alloy temperature deformation spring

Abstract

The application discloses a drop-out fuse based on a memory alloy temperature deformation spring and belongs to the technical field of drop-out fuses. The drop-out fuse comprises temperature deformation spring protection structure and fuse protection structure which are connected in series. The temperature deformation spring protection structure comprises a deformation spring which shrinks with the increase of temperature. The deformation spring is fixedly connected with a rainproof cover and an elastic contact piece which have electric conductivity. The rainproof cover is connected with an external circuit. The fuse protection structure comprises a fuse. A rigid fuse tube is arranged outside the fuse. The fuse tube is rotatably arranged on the external circuit. The fuse tube has an open end and a closed end. The closed end is made of conductive material. The fuse is connected with one side of the closed end. The other side of the closed end is abutted with or disconnected from the elastic contact piece. The fuse is fixedly connected with the external circuit through the open end. The fuse-off temperature of the fuse is higher than the deformation temperature of the temperature deformation spring. Under the double protection of the two protection structures, the working reliability of the protection circuit is improved.

Description

Technical Field

[0001] This invention relates to the field of drop-out fuse technology, and in particular to a drop-out fuse based on a shape memory alloy temperature deformation spring. Background Technology

[0002] Drop-out fuses are widely used in power systems due to their safety, reliability, and excellent cost-effectiveness, playing a protective role. Existing drop-out fuses, such as those described in utility models with application numbers 201820321726.9 and 201920770384.3, both rely on the melting of a fuse wire to cut off the circuit. After the fuse melts, workers must climb the power pole to replace it, resulting in a heavy workload and inherent danger. Replacing the fuse requires a power outage, which is crucial for modern life as electricity is indispensable. Power outages cause economic and social losses and inconvenience to users. Furthermore, the widespread use of drop-out fuses in the power grid consumes a large number of fuses, increasing economic losses. Therefore, to address these problems, this invention provides a drop-out fuse based on a shape memory alloy temperature deformation spring. Summary of the Invention

[0003] The purpose of this invention is to address the defects and shortcomings of the prior art by providing a drop-out fuse based on a shape memory alloy temperature deformation spring, which improves the reliability of the protection circuit under the dual protection of the shape memory alloy temperature deformation spring protection structure and the fuse protection structure.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a drop-out fuse based on a shape memory alloy temperature deformation spring, comprising a shape memory alloy temperature deformation spring protection structure and a fuse wire protection structure connected in series. The shape memory alloy temperature deformation spring protection structure includes a shape memory alloy temperature deformation spring that contracts with increasing temperature. Both ends of the shape memory alloy temperature deformation spring are fixedly connected to a conductive rain cover and an elastic contact, respectively. The fixedly positioned rain cover is connected to the inlet / outlet terminal of an external circuit. The fuse wire protection structure includes a conductive fuse wire with a rigid fuse tube surrounding it. The fuse tube is rotatably mounted on the external circuit and has an open end and a closed end. The closed end is made of a conductive material. The fuse wire is in contact with one side of the closed end, and the other side of the closed end abuts against or is disconnected from the elastic contact. The fuse wire passes through the open end and is fixedly connected to the outlet / inlet terminal of the external circuit. The melting temperature of the fuse wire is higher than the deformation temperature of the shape memory alloy temperature deformation spring. Preferably, the fuse is provided with a conductive disk, the conductive disk is fixedly connected to the fuse tube, and the conductive disk is in contact with the closed end; Preferably, a cap is detachably installed at the closed end of the fusion tube. The cap is made of conductive material, one end of the cap is in contact with the conductive disk, and the other end of the cap is connected to or disconnected from the elastic contact piece. Preferably, the cap has a protrusion, and the elastic contact piece has a groove that matches the protrusion; Preferably, the elastic contact piece is provided with a through hole, and the rain cover is provided with a middle movable steel body adapted to the through hole. The middle movable steel body is inserted into the through hole, and the end of the middle movable steel body does not extend beyond the surface of the elastic contact piece and the tube cap. The contact point between the elastic contact piece and the tube cap is located on the extension line of the middle movable steel body. The front and rear ends of the fusion tube are provided with limiting rods, and an opening for restricting the movement path of the fusion tube is provided between the two limiting rods. The contact point between the elastic contact piece and the tube cap is located on the path defined by the opening, and the size of the opening is adapted to the diameter of the fusion tube. Preferably, the fusible tube is provided with an operating ring that facilitates the installation of the fusible tube into the circuit-on state, and the operating ring is compatible with the operating lever used by the operator; Preferably, a lower stationary contact is fixedly provided on the outlet end / inlet end, and a lower moving contact is installed on the lower stationary contact. One end of the lower moving contact is rotatably connected to the fuse tube, and the other end of the lower moving contact is fixedly connected to the fuse wire. Preferably, the lower moving contact is provided with a pop-out tab for tensioning the fuse, and the length of the pop-out tab is adapted to the tightness of the fuse; Preferably, the pop-out tab is rotatably mounted on the lower moving contact; Preferably, an insulator is provided on one side of the drop-out fuse, one end of the insulator is fixedly connected to the rain cover, and the other end of the insulator is fixedly connected to the lower stationary contact.

[0005] The present invention achieves the following technical effects compared to the prior art: 1. This invention, by setting up a memory alloy temperature deformation spring protection structure and a fuse protection structure connected in series, and with the deformation temperature of the memory alloy temperature deformation spring being lower than the melting temperature of the fuse, achieves the following technical effects: First, when the memory alloy temperature deformation spring is working normally, the heat generated by the large current first causes the memory alloy temperature deformation spring to contract and deform, driving the elastic contact to move upward and disengage from the fuse tube, thereby cutting off the faulty circuit and protecting the circuit. At this time, since the fuse does not melt, it is not necessary to replace the fuse when restoring the circuit, solving many inconveniences caused by replacing the fuse in the prior art and reducing maintenance costs; Second, when the memory alloy temperature deformation spring malfunctions and the staff does not notice or has not had time to replace the memory alloy temperature deformation spring, the heat generated by the large current will melt the fuse, causing the fuse tube to fall under the action of gravity, cutting off the faulty circuit and protecting the circuit; Under the interaction of the memory alloy temperature deformation spring protection structure and the fuse protection structure, the drop-out fuse of this invention can provide dual protection for the circuit, improving the reliability of circuit protection; 2. This invention restricts the reset path of the elastic contact by setting a vertical intermediate movable steel body and providing a through hole on the elastic contact for the intermediate movable steel body to pass through. The engagement position of the elastic contact and the fusible tube is located on the extension line of the intermediate movable steel body. This improves the positional accuracy of the elastic contact after reset. By setting limiting rods on the front and rear sides of the fusible tube, forming an opening between the two limiting rods to restrict the movement path of the fusible tube, and the engagement position of the elastic contact and the fusible tube is located on the path defined by the opening, the reset path of the fusible tube is restricted, improving the positional accuracy of the fusible tube after reset. Under the combined effect of these two methods, the efficiency of reconnecting the circuit is improved when the shape memory alloy temperature deformation spring is working normally. Attached Figure Description

[0006] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0007] Figure 1 This is a schematic diagram of the overall structure of a drop-out fuse. Figure 2 This is a schematic diagram of the cross-sectional structure at point A; Figure 3 This is a schematic diagram of the axonal structure at point A; Figure 4 This is a schematic diagram of the axonal structure at point B; Figure 5 This is a schematic diagram of the axial structure in another direction at point B.

[0008] Among them, 1. Memory alloy temperature deformation spring; 2. Rain cover; 3. Elastic contact piece; 4. Inlet end; 5. Outlet end; 6. Fuse wire; 7. Fusible tube; 8. Open end; 9. Closed end; 10. Conductive disk; 11. Tube cap; 13. Protrusion; 14. Groove; 15. Limiting bracket; 16. Limiting rod; 17. Operating ring; 18. Lower stationary contact; 19. Lower moving contact; 20. First rotating shaft; 21. Second rotating shaft; 22. Lug; 23. Pop-out piece; 24. Insulator; 25. Intermediate movable steel body; 26. Screw; 27. Opening. Detailed Implementation

[0009] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0010] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0011] like Figures 1 to 5As shown, this invention provides a drop-out fuse based on a shape memory alloy temperature deformation spring, comprising a shape memory alloy temperature deformation spring protection structure and a fuse protection structure connected in series. The shape memory alloy temperature deformation spring protection structure includes a shape memory alloy temperature deformation spring 1 that contracts with increasing temperature. The two ends of the shape memory alloy temperature deformation spring 1 are fixedly connected to a conductive rainproof cover 2 and an elastic contact 3, respectively. The fixedly positioned rainproof cover 2 is connected to the inlet terminal 4 / outlet terminal 5 of an external circuit. The fuse protection structure includes a conductive fuse 6, with a rigid fuse tube 7 externally mounted on the fuse 6. The fuse tube 7 is rotatably mounted on the external circuit and has an open end 8 and a closed end 9. The closed end 9 is made of a conductive material. The fuse 6 is in contact with one side of the closed end 9, and the other side of the closed end 9 is in contact with the elastic contact. When the contact piece 3 is connected to or disconnected, the fuse 6 passes through the open end 8 and is fixedly connected to the output end 5 / input end 4 of the external circuit. When the rain cover 2 is connected to the input end 4, the fuse 6 is connected to the output end 5. When the rain cover 2 is connected to the output end 5, the fuse 6 is connected to the input end 4. The melting temperature of the fuse 6 is higher than the deformation temperature of the shape memory alloy temperature deformation spring 1. When a large current passes through the circuit, the large current causes the temperature of the shape memory alloy temperature deformation spring 1 to rise. When the temperature reaches the deformation critical point of the shape memory alloy temperature deformation spring 1, the shape memory alloy temperature deformation spring 1 contracts and deforms. The deformed shape memory alloy temperature deformation spring 1 drives the elastic contact piece 3 to move upward, causing the closed end 9 of the fuse tube 7 to separate from the elastic contact piece 3. The fuse tube 7, which loses the support of the elastic contact piece 3, rotates downward around its rotation fulcrum, thereby cutting off the faulty circuit. Setting the deformation temperature of the shape memory alloy temperature deformation spring 1 to be lower than the melting temperature of the fuse 6 allows the faulty circuit to be cut off by the contraction action of the shape memory alloy temperature deformation spring 1 when it is working normally. Since the fuse 6 has not melted at this time, the entire circuit can be connected by simply restoring the contact connection between the fuse tube 7 and the elastic contact 3 after troubleshooting. This makes maintenance convenient. Moreover, the shape memory alloy temperature deformation spring 1 can be reused with a high reuse limit, and is suitable for circuits of various voltage levels. It does not need to be replaced frequently, which can reduce the number of maintenance operations, improve the safety factor of the staff, and improve economic efficiency. Secondly, if a large current has occurred, but the shape memory alloy temperature deformation spring 1 has not contracted and deformed, the large current will melt the fuse 6. After losing the tension of the fuse 6, the fuse tube 7 will fall rapidly under its own weight, thereby cutting off the faulty circuit. This setting can provide double protection for the circuit and greatly improve the reliability of circuit protection. As a preferred embodiment of the present invention, the shape memory alloy temperature deformation spring 1 has the characteristic that it contracts when the temperature rises and returns to its elongated state when the temperature falls.

[0012] One end of the fuse 6 is provided with a conductive disc 10. In a preferred embodiment of the present invention, the fuse 6 and the conductive disc 10 are integrally formed. A cap 11 is detachably installed at the end of the fuse tube 7 away from the open end 8, and the cap 11 is used to close the opening of the fuse tube 7 to form a closed end 9. The diameter of the conductive disc 10 is adapted to the inner diameter of the opening of the fuse tube 7, so that the conductive disc 10 can be snapped into the opening of the fuse tube 7, which serves to fix the fuse 6. When replacing the fuse 6, after passing the end of the fuse 6 through the fuse tube 7 from top to bottom, the conductive disc 10 is snapped into the opening of the fuse tube 7, and then the cap 11 is tightened. After tightening the cap 11, the inner surface of the cap 11... The cap 11 is in contact with the axial surface of the conductive disk 10. The cap 11 is made of conductive material. When the circuit is connected, the outer surface of the cap 11 away from the conductive disk 10 abuts against the elastic contact 3. When the shape memory alloy temperature deformation spring 1 contracts, the cap 11 is separated from the outer surface of the conductive disk 10 and the elastic contact 3 when the circuit is disconnected. In order to improve the contact performance between the cap 11 and the elastic contact 3, the present invention provides a protrusion 13 on the cap 11 and a groove 14 on the elastic contact 3 that matches the protrusion 13. The protrusion 13 is assembled in the groove 14, which improves the contact stability between the cap 11 and the elastic contact 3.

[0013] The end of the elastic contact 3 away from its fixing point with the shape memory alloy temperature deformation spring 1 is fixedly connected to the rain cover 2. A limiting bracket 15 is also fixedly mounted on the rain cover 2. The limiting bracket 15 has two limiting rods 16, located on the front and rear sides of the fusible tube 7 respectively. The positions of the limiting rods 16 are adapted to the positions where the protrusion 13 engages with the groove 14. An opening 27 is provided between the two limiting rods 16. The engagement position of the fusible tube 7 and the elastic contact 3 is exactly located on the path defined by the opening 27. When the fusible tube 7 is reinstalled, under the limiting effect of the opening 27, the fusible tube 7... When in a vertical position, it is precisely in the snap-fit ​​position with the elastic contact 3. The distance between the limiting rod 16 and the fusible tube 7 in the front-to-back direction should be as small as possible to reduce the positional deviation in the lateral direction when the fusible tube 7 is inserted into the snap-fit ​​position with the elastic contact 3. In addition, a middle movable steel body 25 passes through the middle of the shape memory alloy temperature deformation spring 1. One end of the middle movable steel body 25 is fixed on the rain cover 2, and the other end is inserted into the mounting hole on the elastic contact 3. When the shape memory alloy temperature deformation spring 1 is in the extended state, the end of the middle movable steel body 25 will not exceed the elastic contact 3. The inner surface of the elastic contact 3 is designed to prevent it from exerting a pushing force on the fuse tube 7. When the shape memory alloy temperature deformation spring 1 is in the contracted state, the elastic contact 3 moves along the direction defined by the intermediate movable steel body 25. The intermediate movable steel body 25 is vertically positioned, and the engagement position between the elastic contact 3 and the fuse tube 7 is exactly located on the extension line of the intermediate movable steel body 25. When the circuit is cut off due to the contraction of the shape memory alloy temperature deformation spring 1, after the fault is cleared and the length of the shape memory alloy temperature deformation spring 1 returns to its extended state, there is no need to shut down the power. The operator can use a special tool to reconnect the fuse tube 7 within a safe distance. When the protrusion 13 is inserted into the groove 14, the circuit can be reconnected. During this process, the opening 27 restricts the direction of the pushback of the fuse tube 7, and the moving direction of the elastic contact 3 is restricted by the intermediate movable steel body 25, thereby improving the installation efficiency of reassembling the fuse tube 7 and the elastic contact 3. In order to facilitate the pushback of the fuse tube 7 by the operator, the present invention provides an operating ring 17 on the fuse tube 7. The size and shape of the operating ring 17 are adapted to the insulating operating rod used by the operator. When the circuit is reconnected, the operating ring 17 can be hooked by the insulating operating rod to reconnect the fuse tube 7 back into the circuit.

[0014] In a preferred embodiment of the present invention, the rain cover 2 is connected to the inlet end 4, and a lower stationary contact 18 is fixedly provided on the outlet end 5. The lower stationary contact 18 has a cavity for accommodating the lower moving contact 19, which is placed in the cavity. The lower moving contact 19 has a first rotating shaft 20 and a second rotating shaft 21. The fuse tube 7 has a lug 22, which is rotatably connected to the first rotating shaft 20. The lower stationary contact 18 has a groove for accommodating the second rotating shaft 21, which is detachably installed in the groove. The lower moving contact 19 has a winding mechanism. The protrusion around the fuse 6 is used to fix the upper end of the fuse 6 to the opening of the fuse tube 7, and then the lower end of the fuse 6 is wrapped and fixed to this protrusion. In a preferred embodiment of the present invention, the protrusion is a screw 26 assembled on the lower moving contact 19. The lower moving contact 19 is provided with a pop-out piece 23 for tensioning the fuse 6. The length of the pop-out piece 23 is adapted to the tightness of the fuse 6. The force of the pop-out piece 23 is used to tightly fix the fuse 6 inside the fuse tube 7 and make good contact with the elastic contact piece 3 and the lower moving contact 19. Preferably, the pop-out piece 23 is rotatably mounted on the lower moving contact 19.

[0015] An insulator 24 is provided on one side of the drop-out fuse. One end of the insulator 24 is fixedly connected to the rain cover 2, and the other end of the insulator 24 is fixedly connected to the lower stationary contact 18. The function of the insulator 24 is to provide support and protection, and to provide convenience and protection for the staff during maintenance.

[0016] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention, and no reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A drop-out fuse based on a shape memory alloy temperature deformation spring, characterized in that: The system includes a memory alloy temperature deformation spring protection structure and a fuse protection structure connected in series. The memory alloy temperature deformation spring protection structure includes a memory alloy temperature deformation spring that contracts with increasing temperature. Both ends of the spring are fixedly connected to a conductive rain cover and an elastic contact, respectively. The fixed rain cover is connected to the inlet / outlet terminal of an external circuit. The fuse protection structure includes a conductive fuse with a rigid fusible tube around it. The fusible tube is rotatably mounted on the external circuit and has an open end and a closed end. The closed end is made of a conductive material. The fuse is in contact with one side of the closed end, and the other side of the closed end is either in contact with or disconnected from the elastic contact. The fuse wire passes through the open end and is fixedly connected to the output / input terminal of the external circuit. The melting temperature of the fuse wire is higher than the deformation temperature of the shape memory alloy temperature deformation spring. When the shape memory alloy temperature deformation spring is working normally, the heat generated by the large current first causes the shape memory alloy temperature deformation spring to contract and deform, driving the elastic contact to move upward and disengage from the fuse tube, thereby cutting off the faulty circuit. When the shape memory alloy temperature deformation spring malfunctions and is not detected or replaced by the staff, the heat generated by the large current melts the fuse wire, causing the fuse tube to fall under the action of gravity, cutting off the faulty circuit and protecting the circuit. The characteristic of the shape memory alloy temperature deformation spring is that it contracts when the temperature rises and returns to its elongated state when the temperature falls.

2. The drop-out fuse according to claim 1, characterized in that: The fuse is provided with a conductive disk, which is fixedly connected to the fuse tube and is in contact with the closed end.

3. The drop-out fuse according to claim 2, characterized in that: The closed end of the fusion tube is detachably fitted with a tube cap made of conductive material. One end of the tube cap is in contact with the conductive disk, and the other end of the tube cap is connected to or disconnected from the elastic contact piece.

4. The drop-out fuse according to claim 3, characterized in that: The cap has a protrusion, and the elastic contact piece has a groove that matches the protrusion.

5. The drop-out fuse according to claim 3, characterized in that: The elastic contact piece has a through hole, and the rain cover has a middle movable steel body adapted to the through hole. The middle movable steel body is inserted into the through hole, and the end of the middle movable steel body does not extend beyond the surface of the elastic contact piece that contacts the cap. The contact point between the elastic contact piece and the cap is located on the extension line of the middle movable steel body. The front and rear ends of the molten tube are provided with limiting rods, and an opening for restricting the movement path of the molten tube is provided between the two limiting rods. The contact point between the elastic contact piece and the cap is located on the path defined by the opening, and the size of the opening is adapted to the diameter of the molten tube.

6. The drop-out fuse according to claim 5, characterized in that: The fusible tube is provided with an operating ring that facilitates its installation in the circuit-on state, and the operating ring is compatible with the operating lever used by the operator.

7. The drop-out fuse according to claim 1, characterized in that: A lower stationary contact is fixedly provided on the outlet / inlet end, and a lower moving contact is installed on the lower stationary contact. One end of the lower moving contact is rotatably connected to the fuse tube, and the other end of the lower moving contact is fixedly connected to the fuse wire.

8. The drop-out fuse according to claim 7, characterized in that: The lower moving contact is provided with a pop-out tab for tensioning the fuse, the length of which is adapted to the tightness of the fuse.

9. The drop-out fuse according to claim 8, characterized in that: The pop-out tab is rotatably mounted on the lower moving contact.

10. The drop-out fuse according to claim 7, characterized in that: An insulator is provided on one side of the drop-out fuse. One end of the insulator is fixedly connected to the rain cover, and the other end of the insulator is fixedly connected to the lower stationary contact.

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